A Completely Automated Public Turing test to tell Computers and Humans Apart (“Captcha”) is a type of challenge-response test used in computing to determine whether or not a user is human. A captcha is a program or system intended to distinguish between human and machine input to prevent robots or other non-human interactors to access network locations, such as webpages. Captchas are often used as a way of thwarting spam and automated extraction of data from websites.